[LinuxPPS] can't get ntp syncing with palisade and atom drivers

[Ian Bobbitt]

On Dec 11, 2008, at 3:04 PM, Hal V. Engel wrote:

> On Thursday 11 December 2008 07:46:02 Ian Bobbitt wrote:
>> I'm using kernel 2.6.27.8 with the ntp-pps-2.6.27-rc3-bis.diff patch
>> applied. I'm trying the ntp-dev-4.2.5p149 development tag of ntp.
>> Does anyone know what's going wrong and how I can get it going right?
>>
>> I'm able to see the pps signal if I use ppstest:
>>
>> [root at ntp pps]# ./ppsldisc /dev/ttyS1 &
>> [1] 4742
>> [root at ntp pps]# ./ppstest /dev/pps0
>> trying PPS source "/dev/pps0"
>> found PPS source "/dev/pps0"
>> ok, found 1 source(s), now start fetching data...
>> source 0 - assert 1229009608.010237952, sequence: 5 - clear
>> 1229009609.010162833, sequence: 6
>> ^C
>> [root at ntp pps]#
>
> PPS is working but there are two things I notice that are a little  
> odd.  First
> the PPS pulse is very short at about 105 microseconds.  This may not  
> a an
> issue with your driver.  Second on any given sequence the assert  
> happens AFTER
> the clear.  This last one indicates to me that the PPS pulse is  
> inverted.
>

It's entirely possible the signal is inverted but I gather it's a  
simple mode change in ntp.conf away from being correct? I can check  
with a 'scope to confirm, but I don't believe that's my current problem.

>> ## 22 is PPS "ATOM" device
>> server 127.127.22.0 minpoll 4 maxpoll 6
>> fudge  127.127.22.0 flag2 1 flag3 1
>>
>> # Palisade driver, mode 1 is praecis in trimble emul mode
>> #server 127.127.29.0 mode 1 prefer
>> #fudge 127.127.29.0 refid CDMA
>
> You have mode set to 1 which would indicate that you are using an "  
> Endrun
> Praecis in Trimble emulation mode".  This that correct?  If it is  
> not then
> this may be your issue.

Yes, this is correct as I'm using a Praecis Cf in trimble emulation  
mode.

My current suspicion is an odd interaction between the palisade driver  
opening the port incorrectly causing the pulses to not be captured  
since I can use either one, but not both at the same time.